Ship&#39;s plate.



PATENTED APR. 23, 1907. J. CRAIG.

SHIPS PLATE] APPLICATION FILED mm 22, 1905.

n M J ATTORNEY.

mg to prov1d JOHN CRAIG, OF SAN FRANCISCO, CALIFORNIA.

SHIPS PLATE.

Specification of Letters Patent.

Patented A ril as, 1907.

Application filed June 22, 1905. Serial No. 268,401.

To all whom it may concern.-

Be it known that I, JOHN CRAIG, a citizen of the United States, residing at San' Franclsco, 1n the county of San Francisco and State of California, have invented certain new and useful Im rovements in Ships tIflates, of whioh the f llowing is a specifica- This invention relates to improvements in shlps plates, the object of the invention bee an improved form of plate which Wlll be cheaper and more durable than those heretofore used.

It 1s at present the practice in cop ering an iron vessel tofirst cover the whol e of the' ship with wood and then tack the copper sheathing on to the wood.

' of a wel It is the object of the resent invention to prov de a plate which wi avoid the necessity of this operation. For this purpose I employ the following process. The plate is taken as 1t comes from the furnace and placed immedlately m a mold so that it is of substantially the same temperature as in the furnace. The copper, having been previously melted, is then poured upon the surface of the steel in the mold. The plate is then allowed to cool. The tem erature of the steel must always be ing from the furnace. However, in certain cases it may be necessary to bring the steel to this temperature from a cold condition, and this I consider to be within the scope of my invention. The term welding heat is used in its general acceptation, namely, that at which the steel isin a soft condition, not so soft as to lose its shape, but ready to run if raised to any greater temperature. In other'words'it must be raised to as high a temperature as possible and et be self-supporting. The temperature 0 the steel being above the melting oint of cop erl-the latter lies upon the steel p ate in amo ten sheet and.

solidifies slowl in contact therewith as the platescools. I e coating oflcast copper so metals.

111g heat and this it will be on comroduced is not onl homogeneous and dense,

ut it adheres to t e steel in a more perfect manner than can be secured bany other means of which I am aware. perfect adhesion is due to the fact that when the 0 metals are brought into contact the steel .is in a soft but not a fluid condition, whereas the cop er is molten; this relation permits only suc interpenetration of the respective metals as 1s necessary to secure a perfect 5 union of the plates, and without obliterating the surface of demarcation between the If the temperature of the steel were below its softening point there could be no such inte enetration and hence no such perfeet attac cut; and if both metals were molten the interpenetration would be such as to completely obliterate the surface of demarcation and to form alloys of low tensile strength, thereby weakening the entire plate. 6 5

The cop er late so a lie may be made of an desii'ed thicknessii he accompanying drawing illustrates in transverse section a ships plate constructed in accordance with my invention. 1 repre- 7o sents the steel late and 2 the copper plate, the surface oi demarcation between the plates being indicated by 3.

I claim A ships plate consisting on one side of a steel plate and on the other side of a dense and homogeneous plate of cast copper, the surface of demarcation between sai plates being sharply defined, but the respective metals interpenetrat to such extent as to secure perfect union r the plates, substantially as described.

In witness whereofI have hereunto set my hand in the presence of two subscribing witnesses.

I JOHN CRAIG.

Witnesses:

Fnancrs M. Warcn'r,

K. L. Nnvnws. 

